1. Field of the Invention
The present invention relates to a superconducting magnet device using an intermetallic compound superconducting coil and, more particularly, to an intermetallic compound superconducting coil suitable for use with a superconducting magnet device for high magnetic fields of the so-called "medium or large size", which reserves energy exceeding one megajoule as a result of application of a high electromagnetic force.
2. Description of the Prior Art
In recent years, as an intermetallic compound superconducting coil for generating a high magnetic field of 13 to 15 teslas, there has been used an intermetallic compound superconducting coil which is made of Nb.sub.3 Sn and V.sub.3 Ga.
This superconducting magnet device using the superconducting coil made of an intermetallic compound such as Nb.sub.3 Sn or V.sub.3 Ga is disclosed, for example, in FIGS. 1 and 2 of Japanese Patent Laid-Open No. 54-120882, entitled "Superconductor".
Specifically, the superconductor as disclosed in FIG. 2 of the Japanese Patent Laid-Open No. 54-120882 is produced by forming superconducting wires of an intermetallic compound such as V.sub.3 Ga and a Cu--Ga alloy into an intermetallic compound complex superconductor region and by burying the complex superconductor region in a groove of a copper stabilizer so as to thermally stabilize a resultant superconducting coil. The superconductor thus produced has a defect that it is deformed, if a strong electromagnetic force (which is equal to or stronger than 10 Kg/cm.sup.2 for the coil of a medium or larger size) is applied thereto, to have its characteristics deteriorated.
Moreover, the superconductor requires a large quantity of copper stabilizer for retaining the stability of the large-sized coil. In order to retain a strength sufficient to endure the electromagnetic force, still moreover, the sectional area of the stabilizer itself has to be enlarged. As a result, the superconducting coil using such intermetallic compound superconductor has its overall current density reduced for the whole coil so that it cannot be applied to a superconducting magnet device of medium or larger size for a high magnetic field requiring a high current density.
On the other hand, the superconductor as disclosed in FIG. 2 of the Japanese Patent Laid-Open No. 54-120882 is produced by arranging a reinforcement member of stainless steel or the like at the center of a region of an intermetallic compound complex superconductor. The superconductor thus prepared is sufficient for the strength and the thermal stability but it finds it remarkably difficult to produce a long conductor because it is made of such a complex material as has difficult workability.